Electrophotographic photoreceptor

Abstract

An electrophotographic photoreceptor having on a conductive support an interlayer and a photoconductive photoreceptive layer in that order, with the interlayer containing at least one colloidal substance selected from colloidal silica and colloidal alumina, and an organic solvent soluble resin which is composed of (A) a polymer having an acid value of from 10 to 100 and containing repeating units represented by formula (I) and (II) <IMAGE> (I) wherein R1 represents H or CH3; R2 represents H, -CH3, -C2H5, or a chloromethyl group; and n represents an integer of 1 to 10; <IMAGE> (II) wherein R3 represents H or -CH3; and (B) at least one polymer selected from a homopolymer and a plural copolymer having a glass transition point (Tg) of from -70 DEG to 20 DEG C., which can be utilized as a lithographic printing material having long press life.

What is claimed is: 
     
       1. An electrophotographic photoreceptor in which an interlayer and a photoconductive photoreceptive layer are provided on a conductive support in that order, said interlayer comprising at least one colloidal substance selected from the group consisting of colloidal silica and colloidal alumina, and an organic solvent soluble resin which is composed of: (A) a polymer having an acid value of from 10 to 100 and containing repeating units represented by formula (I) in the range of 30 to 80 wt.% and formula (II) in the range of 5 to 60 wt.%, based on the total weight of the polymer A: ##STR8##  wherein R 1  is H or CH 3  ; R 2  is H, --CH 3 , --C 2  H 5 , or a chloromethyl group; and n is an integer of 1 to 10; and ##STR9##  wherein R 3  is H or --CH 3  ; and (B) 5 to 30 parts by weight per 100 parts by weight of polymer (A) of at least one polymer selected from the group consisting of a homopolymer and plural copolymer having a glass transition point (Tg) of from -70 ° to 20° C.;   said colloidal substance being used in an amount of 30 to 300 parts by weight based on solid component per 100 parts by weight on the basis of solid component of said organic solvent-soluble resin; and said interlayer being provided in a coverage of 1.5 to 10.0 g/m 2 .   
     
     
       2. An electrophotographic photoreceptor as in claim 1, wherein said conductive support is a sheet of paper which contains an electrically conductive substance and has laminated to at least one side thereof a polyethylene layer having a thickness of from 5 to 50 μm and containing carbon black in a concentration of from 5 to 30% by weight. 
     
     
       3. An electrophotographic photoreceptor as in claim 1, wherein the polymer (A) has an acid value of from 15 to 40. 
     
     
       4. An electrophotographic photoreceptor as in claim 1, wherein the organic solvent-soluble resin comprises from 10 to 40 wt% the repeating unit represented by formula (II), from 40 to 60 wt% the repeating unit represented by formula (I), and from 5 to 30 parts by weight of polymer (B) per 100 parts by weight of polymer (A). 
     
     
       5. An electrophotographic photoreceptor as in claim 1, wherein the colloid substance has an average grain size of from 5×10 -5  to 1×10 -7  cm. 
     
     
       6. An electrophotographic photoreceptor as in claim 2, wherein the colloid substance has an average grain size of from 5×10 -5  to 1×10 -7  cm. 
     
     
       7. An electrophotographic photoreceptor as in claim 1, wherein the interlayer is provided in a coverage of from 3.0 to 6.0 g/m 2 . 
     
     
       8. An electrophotographic photoreceptor as in claim 1, wherein the photoreceptive layer comprises a photoconductive material and a binder. 
     
     
       9. An electrophotographic photoreceptor as in claim 8, wherein the photoconductive material is zinc oxide.